Re: [IRCA] WWNN breaking the rules.

Good points, all.

Keep in mind that no station putting HD on the air is looking for anything except audience in their immediate local groundwave coverage area. There is literally no revenue for audience outside a station’s own metro (save maybe tow or three exceptions) so the fact that HD seems to cover the clean signal area better than analog in many real world test situations supports its usage. In several tests I have been a part of, the usable HD signal extends beyond the usable analog area, so this is a very big thing for us.

From: irca-bounces@xxxxxxxxxxxxxxxx [mailto:irca-bounces@xxxxxxxxxxxxxxxx] On Behalf Of W. Curt Deegan
Sent: Wednesday, November 23, 2005 12:43 PM
To: Mailing list for the International Radio Club of America
Subject: Re: [IRCA] WWNN breaking the rules.

Barry,

I monitored WWNN until about 0130est last night. They never dropped IBOC and definitely were on day power. I determined that today when I could see there was no difference from last night.

It is interesting you found no IBOC signal. I don't think anyone has any idea what will happen with the skywave component of the IBOC sidebands. That was my reason for posting the WWNN screw up last night, thinking maybe someone might hear something. Since there are virtually no HD radios, I didn't expect anyone to actually be able to try to listen, but hearing the IBOC hiss interfering with adjacent channels on skywave would have been an interesting event.

As my tests show -- link below in signature -- the IBOC sidebands drop off very fast compared to the analog part of the hybrid signal when looking at ground wave with antennas of varying gain. Others have reported a similar rapid drop off of the IBOC sidebands with increasing distance, more so that the analog component of the signal.

This would seem to indicate a usable HD ground wave signal will cover less of a range than a normal analog signal. It remains to be determined what happens to the skywave and what if any damage it will do without the hope of actually reaching any potential audience.

Curt.